1. Field of the Invention
The present invention is directed to a device for tracking moving light sources, such as, but not limited to, a heliostat. More particularly, the invention is directed to a light tracking device that is self-contained and self-powered for operation, for use with or in, for example, solar energy applications.
2. Discussion of Related Art
For some time it has been recognized that solar energy is a desirable source of energy as it is clean, i.e., does not produce any hazardous by-products, is readily available and inexhaustible. However, solar panels and collectors are expensive and, in order to obtain efficient operation, it is desirable to maximize sunlight absorbed by the panels and/or collectors. Therefore, it is necessary to compensate for (i.e., track) the changing direction of the sunlight caused by the sun's apparent motion through the sky, and keep the panels aimed at the sun. This requires a moving light tracking device. One type of such a device is known as a “heliostat.” A heliostat is an instrument including a mirror that is automatically moved by a clockwork mechanism so as to reflect sunlight (or light from another bright source) in a fixed direction. Thus, using a heliostat, a beam of sunlight may be steadily directed to one spot during most or all of the whole diurnal period of daylight from the sun. However, in some applications it is not necessary to move a mirror and the object of the tracking device may be to keep solar devices aimed at the sun and use, for example, their electrical output to drive a load (e.g., a radio) directly.
Conventional heliostats are economically and practically unfeasible or undesirable for some applications because they are expensive and include complicated machinery. Conventional heliostats usually include a computer or microprocessor adapted to control the positioning of the heliostat mirror, taking into account the latitude and longitude of the location of the heliostat. Thus, set-up of the heliostat may be an involved process that may include programming the computer with the geographic coordinates of the location of the heliostat. Computers are expensive, adding to the overall cost of conventional heliostats. Known heliostats also require an external power supply, for example a sizeable battery or a.c. mains supply, to power the computer, other electronics, and motor needed to move the mirror and other components of the heliostat to keep the mirror properly aligned with the sun. The external power supply also adds to the cost, bulkiness and weight of conventional heliostats. Due to such cost, bulkiness and weight factors, and sometimes the need for an a.c. mains supply, conventional heliostats are rendered unsuitable for many applications, for example camping or other remote location uses, where the heliostat would need to be portable, or small and light, or preferably inexpensive and easy to set-up.